Advanced CNC Milling and Drilling Quiz

(Text updated February 4, 2019) Ryan Pohl of Praeco Skills developed this test to quickly evaluate students' knowledge of CNC milling and drilling and determine the level of instruction they need. What is your TNMG Insert level of knowledge? Scroll down to read the questions and find an answer key or take the quiz interactively here.

1. What is the maximum rpm you should run a holder if it is unbalanced in a V-tapered spindle?

 __ 4,000 rpm__ 6,000 rpm__ 8,000 rpm__ 10,000 rpm  2. Unless it has a special design to ensure Z-Axis accuracy, V-tapered tooling should never be run faster than… __ 6,000 rpm__ 8,000 rpm__ 10,000 rpm__ 12,000 rpm  3. Countless tests have proven which of the following tool tapers to be superior in radial and axial stiffness, z-axis repeatability and performance for high speeds? __ CAT__ HSK__ BT__ SK  4. You should never use a cutter that has _________________ in a hydraulic holder, a milling chuck or in high speed applications. __ Weldon flats__ Hybrid TCGT Insert coatings__ Multiple inserts__ Through-spindle coolant  5. One of the key limiting factors of a C-frame mill design is… __ Workpiece visibility__ Top-end rpm__ Tool-magazine capacity__ Y-axis rigidity  6. What is the name of the rotational axis that corresponds with the Y-linear axis? __ A-axis__ B-axis__ C-axis__ W-axis  7. The machine ____________ plays a key role in isolating and absorbing vibrations and shock from the cutting operation on the machine as well as surrounding impacts on the shop floor. __ Column__ Frame__ Ways__ Foundation  8. If the _________________ is too long on a machine, it may whip in the center, causing machine-component- and part-damaging vibrations. __ Linear Guide Way__ Ball Screw__ Rack and Pinion__ Box Way  9. Using a ________________ in your CAM program eliminates 90 degree corner moves, saving on tool and machine life, as well as increasing part quality. __ Radial Lead-in__ Smoothing-radius__ Collision check__ Radial Step-over  10. A material’s machinability rating is a(n) _______________ value given to a particular material’s ease with which it is machined. __ Objective__ Subjective__ Standardized__ Letter  11. ________________________ is a measure of the linear-distance that a single point on the outside edge of the cutter is moved around the circumference as the cutter rotates in one minute. __ Feed rate__ Cutting Speed__ RPM__ Chip load  12. Using (an) _________________ can destroy the effectiveness and efficiency of a cut when machining ferrous alloys with coated-carbide cutters. __ Flood coolant__ Air blast__ Air/Mist blast__ Chipbreakers  13. When taking a depth of cut that is smaller than the full radius of the cutter, the actual amount of the cutter that is engaged into the workpiece is called the… __ Actual Diameter__ Actual Engagement__ Effective Radius__ Effective Diameter  14. A standard for maximum Length to Diameter (L:D) ratio for normal sized (not micromachining) cutters being held outside the holder, without having to slow rpm and feed, is… __ 2:1__ 3:1__ 4:1__ 5:1  15. _____ is a man-made synthetic cutter that has greater thermal resistance than diamond. __ CBN__ CVD__ PCBD__ PCD  16. _____________ is the secondary ingredient used in tungsten carbide cutters that acts as a binder, and has a dramatic affect on the overall hardness of the carbide itself. __ Aluminum__ Iron-carbide__ Cobalt__ Silicon  17. The ________________ of the cutter is responsible for generating the essential aluminum-oxide in a high-speed cut in ferrous materials. __ Geometry__ Thickness__ Speed__ Coating  18. To perform high speed machining, all holders and components should be balanced to a rating of _________ for the rpm they will be run. __ G1.0__ G1.5__ G2.0__ G2.5  19. High speed machining (which might more appropriately be called “High-Efficiency Machining”) works because the ______________ and ______________ are controlled at the point of cut. __ Heat, Vibration__ RPM, Feed rate__ Loads, Limits__ Time, Temperature  20. High-speed machining begins at 8,000 rpm and 100 ipm. __ True__ False  

For the answer key, click here.

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